A novel fourth order chaotic system and its algorithm for medical image encryption

Today, medical imaging suffers from serious issues such as malicious tampering and privacy leakage. Encryption is an effective way to protect these images from security threats. Chaos has been widely used in image encryption, the majority of these algorithms are based on classical chaotic systems. For now, these systems are easy to analyze and predict, which are not sufficient for image encryption proposes. In this paper, a novel fourth order chaotic system is proposed, accompanied by analysis of Lyapunov exponent and bifurcations. Finally, the application of this system with medical image encryption is proposed. As this system could have six control parameters and four initial conditions, the key space is far greater than 5.1 x 2(18191), which is large enough to resist brute force attack. Correlation analysis and differential attack analysis further demonstrate that this scheme has a strong resistance against statistical attacks and differential attack.